Innate immunity: Pattern recognition receptors and signalling

Question 1

Describe what Candida albicans can cause

Answer 1

Fungus infection = can cause severe septic shock
Certain pop of individuals = more susceptible
Fungus activates alternative pathway of complement

Question 2

Describe gros lab experiment set up

Answer 2

Study compared genetics of 2 strains of mice = one susceptible and one relatively resistant to infection
Analysis of genomes showed that susceptible strain had deletion in gene that coded for c5a
Mice of each strain infected with c albicans then load of fungus determined

Question 3

What are observed results of gros research lab activity

Answer 3

Susceptible mice have higher load of c albicans

Question 4

What are CONCLUSIONS of gros research lab activity

Answer 4

C5a needed to clear c albicans = functional role important

Question 5

WHAT do pathogens have

Answer 5

Specific molecular patterns that support their lifestyle = pamps

Question 6

What are pamps recognized by

Answer 6

Prrs = on host cells, in host cells (can be intracellular) and are host soluble proteins
Range of locations = ensures that cells can recognize pamps of virtually any pathogen

Question 7

What is also recognized by prrs

Answer 7

Damps = damage associated molecular patterns

Question 8

Which cells have prrs

Answer 8

All types of myeloid wbcs
Subset of lymphoid cells = some T cells, B cells and nk cells = part of innate immune response

Question 9

Describe prrs expressed by some other cell types

Answer 9

Those common exposed to infectious agents = epithelial cells of skin and mucosal tissues and endothelial cells that line blood vessels leading to production of antimicrobial substances

Question 10

What is expressed by most if not all cells in body

Answer 10

Cytosolic sensors of viral nucleus acids

Question 11

Where are prrs located

Answer 11

At diff sites depending on pamp they recognize = cell surface, intracellular or secreted

Question 12

Name groups of prrs

Answer 12

Toll like receptors = tlrs
Nod like receptors = nlrs
Rig I like receptors = rlrs
C type lectin receptors = clrs
Ficolins, mannose binding lectins, c1q
Others

Question 13

What do prrs activate

Answer 13

Signalling pathways = contributing to innate/inflammatory response

Question 14

Compare cell surface bc intracellular prrs

Answer 14

Bind on surface = pamp on surface = lipopeptides, flagellin, lps
Intracellular = binds nucleic acids mainly = rna and dna

Question 15

Describe toll like receptors

Answer 15

Extracellular= bind bacteria, parasites, fungi = cell wall, gram neg bacteria
Intracellular = still membrane bound to vesicle or endoscope =more viral, nucleic acids
Intracellular vs Extracellular receptors = logic behind corresponding pamps = location helps determine what binds

Question 16

What does tlr binding of pamps do

Answer 16

Activates signalling pathways
Diff tlrs recruit diff adaptor proteins = link protein binding partners together and facilitate large signaling complexes
Diff adaptor proteins lead to diff events

Question 17

Name and describe adaptor proteins/events

Answer 17

Nf-kB transcription factor activation
Interferon regulating factor = irf pathways
Map kinase pathway downstream transcription factors = ap-1

Question 18

What are transcription factors

Answer 18

Nf-k-B,irf and ap-1 = tfs
In cytoplasm —> activated —> nucleus

Question 19

End result of signalling and gene expression

Answer 19

Signalling leads to activation of tfs —> transcription of innate immune/pro-inflammatory genes
Once genes expressed = have specific impacts

Question 20

Describe signalling cascade

Answer 20

Signalling cascade triggered = involves many proteins
Phosphorylation = key event,addition of phosphoryl group to molecule = leads to activation of tfs, translocate into nucleus to activate gene expression

Question 21

What are key molecules

Answer 21

Adaptor proteins = myD88, TRIF
Transcription factors = irf3/7, nf-kb, ap-1

Question 22

Name and describe all general features of signal transduction

Answer 22

Ligand induced receptor dimerization —> recruitment/activation of kinases and adaptors —> Second messenger = through phosphorylation, ca, camp, dag, etc —> activation/nuclear translocation of tfs —> Changes in gene expression —> Post transcriptional or translational mods —> Functional response —> secreted out of cell —> functional

Question 23

Describe central dogma

Answer 23

Dna —transcription—> mRNA —translation—> protein
Each gene has promoter
Tfs bind specific sequences on promoter = response element
Recruits rna polymerase =
Transcription begins

Question 24

Describe what western blot can detect

Answer 24

Proteins and their phosphorylation =
When recruit/activate kinase and adaptor and when second messengers

Question 25

Describe what can see activation / nuclear translocation of transcription

Answer 25

Proteins and their phosphorylation can be isolated form nucleus and detected and their binding to promoter regions can be determined

Question 26

What is rt pcr used for

Answer 26

Detect mRNA = when changes in gene expression

Question 27

When use northern bblot

Answer 27

mRNA stability/splicing can be detected and determined - pre or post cleavage = when post transcriptional or translational mods

Question 28

When can Extracellular protein be detected

Answer 28

After secreted out of cell = when have functional response

Question 29

Describe c type lectin receptors = what type

Answer 29

Membrane receptros = on surface

Question 30

Describe c type lectin receptors = what bind

Answer 30

Binds carbohydrates on pathogen and some allergens = peanut, dust mite proteins

Question 31

Describe c type lectin receptors = cascade

Answer 31

Activated tyrosine kinases trigger signalling cascade =
Card adaptor protein
Irf5 activation = tf
Map kinase pathways activation = result in activation of ap-1 and nf-kB = tfs go into nucleus and
Induce expression of inflammatory cytokines

Question 32

Describe rig I like receptors = function

Answer 32

Function as cytosolic prrs = inside cell

Question 33

Describe rig I like receptors = detect

Answer 33

Recognize viral double stranded rnas and certain structured single stranded rna = mainly viral

Question 34

Describe rig I like receptors = mavs

Answer 34

Mitochondrial antiviral signalling protein = card connects rig I to mavs

Question 35

Describe rig I like receptors = signalling pathways

Answer 35

Mavs trigger signalling pathways that activate irfs and nf-kb = tfs
Then translocation and transcription

Question 36

What does nod like receptors stand for

Answer 36

Nucleotide oligomerization domain

Question 37

Describe nlrs function

Answer 37

Cytosolic prrs
Some floating or anchored = on endosome

Question 38

Describe nlrs recognize

Answer 38

Peptidoglycan from bacterial cell wall - must enter Cytosol
When phagocytosis= in phagosome = chop up, so pieces peptidoglycan can be recognized by nlrs

Question 39

Describe nlrs = triggers what

Answer 39

Nf-kb and ap-1 and irf signalling = tfs

Question 40

Describe nlrs = activates what

Answer 40

Caspase 1 protease
Cleaves il-1beta/il-18 into active forms = for release of pro inflammatory cytokines
= POST TRANSLATIONAL MOD

Question 41

Describe nlr post translational modification

Answer 41

Pro cytokines = pro-il-1beta + pro-il-18, active caspase 1 cleaves and makes ready to be secreted = il-1beta and il-18

Question 42

Describe prr signalling pathway mods = which 2 types

Answer 42

phosphorylation and ubiquitination

Question 43

Describe ubiquitination

Answer 43

Process of attachment of one or many subunits of ub to target protein = can mediate their formation for further signalling = activation sometimes but mostly degradation of protein

Question 44

What can prr signalling pathways result in

Answer 44

Post transcriptional and post translational mods

Question 45

What is ultimate goal prr signalling

Answer 45

To Carry out function = cytokines, other signalling molecules